Analysis of the regulation of permeability via lens fiber cell gap junctions has been accelerated recently with the advent of techniques to extract the junctional components and reinsert them into artificial membrane bilayers. These techniques, as developed and utilized in our laboratory, will be combined with another biophysical methodology (Langmuir-Blodgett monolayers) in order to elucidate the effects of pH changes in junctional gating and junctional protein conformation. The interactions of known junctional components with membrane lipids and with other membrane proteins will be examined, in order to ascertain if these components also contribute to pH-gated permeability in reconstituted membranes. We will also examine the hypothesis that junctional proteins from human cataractous lens fiber cells are defective in their response to changes in pH, using both the permeability assay and monolayer techniques designed to furnish structural information. The use of two powerful biophysical techniques will allow us to probe the relationship of structure and function in these functionally active membrane channels. This information will be valuable in determination of the molecular mechanisms of cataractogenesis in older human beings, and potentially could represent an entirely new approach to the study of other channel-forming proteins such as neurotransmitter receptors and ion antiporters.